CREATE TABLE users (
    id SERIAL PRIMARY KEY,
    username VARCHAR(50) NOT NULL UNIQUE,
    email VARCHAR(255) NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    display_name VARCHAR(100),
    avatar_path TEXT,
    instagram_url VARCHAR(500),
    profile_visibility VARCHAR(20) NOT NULL DEFAULT 'friends'
        CHECK (profile_visibility IN ('public', 'friends', 'nobody')),
    is_admin BOOLEAN NOT NULL DEFAULT FALSE,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE account_tokens (
    id SERIAL PRIMARY KEY,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    purpose VARCHAR(30) NOT NULL CHECK (purpose = 'password_reset'),
    token_hash TEXT NOT NULL UNIQUE,
    expires_at TIMESTAMP NOT NULL,
    used_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX idx_account_tokens_lookup
    ON account_tokens (token_hash, purpose, expires_at);

CREATE TABLE friendships (
    id SERIAL PRIMARY KEY,
    requester_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    addressee_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    status VARCHAR(20) NOT NULL DEFAULT 'pending'
        CHECK (status IN ('pending', 'accepted')),
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    CHECK (requester_id <> addressee_id),
    UNIQUE (requester_id, addressee_id)
);

CREATE UNIQUE INDEX idx_friendships_pair
    ON friendships (LEAST(requester_id, addressee_id), GREATEST(requester_id, addressee_id));

CREATE TABLE direct_messages (
    id SERIAL PRIMARY KEY,
    sender_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    recipient_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    body TEXT NOT NULL,
    read_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    CHECK (sender_id <> recipient_id)
);

CREATE INDEX idx_direct_messages_conversation
    ON direct_messages (sender_id, recipient_id, created_at);

CREATE INDEX idx_direct_messages_unread
    ON direct_messages (recipient_id, read_at);

CREATE TABLE registration_invites (
    id SERIAL PRIMARY KEY,
    token_hash TEXT NOT NULL UNIQUE,
    expires_at TIMESTAMP,
    used_by INTEGER REFERENCES users(id),
    used_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE sessions (
    id SERIAL PRIMARY KEY,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    token_hash TEXT NOT NULL UNIQUE,
    expires_at TIMESTAMP NOT NULL,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE venues (
    id SERIAL PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    street VARCHAR(255),
    postal_code VARCHAR(20),
    city VARCHAR(100),
    country VARCHAR(100) DEFAULT 'Deutschland',
    latitude DOUBLE PRECISION,
    longitude DOUBLE PRECISION,
    external_id VARCHAR(255),
    source VARCHAR(50),
    is_verified BOOLEAN NOT NULL DEFAULT FALSE,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE venue_aliases (
    id SERIAL PRIMARY KEY,
    venue_id INTEGER NOT NULL REFERENCES venues(id) ON DELETE CASCADE,
    alias VARCHAR(255) NOT NULL,
    UNIQUE (venue_id, alias)
);

CREATE TABLE concerts (
    id SERIAL PRIMARY KEY,
    artist VARCHAR(255) NOT NULL,
    event_type VARCHAR(20) NOT NULL DEFAULT 'concert'
        CHECK (event_type IN ('concert', 'festival', 'other')),
    parent_event_id INTEGER REFERENCES concerts(id) ON DELETE SET NULL,
    venue_id INTEGER REFERENCES venues(id) ON DELETE SET NULL,
    start_datetime TIMESTAMP NOT NULL,
    end_datetime TIMESTAMP,
    description TEXT,
    ticket_url TEXT,
    ticket_price NUMERIC(10,2),
    flyer_path TEXT,
    flyer_url TEXT,
    created_by INTEGER REFERENCES users(id) ON DELETE SET NULL,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE concert_comments (
    id SERIAL PRIMARY KEY,
    concert_id INTEGER NOT NULL REFERENCES concerts(id) ON DELETE CASCADE,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    body TEXT NOT NULL,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE concert_photos (
    id SERIAL PRIMARY KEY,
    concert_id INTEGER NOT NULL REFERENCES concerts(id) ON DELETE CASCADE,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    path TEXT NOT NULL,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE concert_attendance (
    concert_id INTEGER NOT NULL REFERENCES concerts(id) ON DELETE CASCADE,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    status VARCHAR(20) NOT NULL CHECK (
        status IN ('attending', 'maybe', 'ticket_search', 'ticket_offer')
    ),
    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (concert_id, user_id)
);

CREATE TABLE user_badges (
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    badge_code VARCHAR(50) NOT NULL,
    awarded_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (user_id, badge_code)
);

CREATE INDEX idx_concerts_start_datetime
    ON concerts(start_datetime);

CREATE INDEX idx_venues_name
    ON venues(name);

CREATE INDEX idx_venues_external_id
    ON venues(external_id);

CREATE INDEX idx_venue_aliases_alias
    ON venue_aliases (LOWER(alias));

CREATE INDEX idx_concerts_parent_event_id
    ON concerts(parent_event_id);

CREATE INDEX idx_concert_comments_concert
    ON concert_comments(concert_id, created_at);

CREATE INDEX idx_concert_photos_concert
    ON concert_photos(concert_id, created_at);

CREATE INDEX idx_concert_attendance_concert
    ON concert_attendance(concert_id, status);